Craft CMS Security Challenges: Understanding the RCE Exploit Chain

Craft CMS Security Challenges: Understanding the RCE Exploit Chain

Alex Cipher's Profile Pictire Alex Cipher 5 min read

Craft CMS, a popular content management system, recently faced a significant security challenge with a remote code execution (RCE) exploit chain. This exploit chain, identified as CVE-2025-32432, allowed attackers to execute arbitrary code on servers by manipulating a “return URL” parameter. The vulnerability was actively exploited in zero-day attacks, leading to data breaches and server compromises, as reported by Orange Cyberdefense’s CSIRT. Additionally, an input validation flaw in the Yii framework, CVE-2024-58136, compounded the issue by enabling PHP code execution through malicious JSON payloads. These vulnerabilities highlight the critical need for robust security measures and timely patching in content management systems.

Overview of Vulnerabilities in Craft CMS RCE Exploit Chain

Remote Code Execution Vulnerability in Craft CMS

The Craft CMS platform was found to have a significant remote code execution (RCE) vulnerability, identified as CVE-2025-32432. This vulnerability allows attackers to execute arbitrary code on the server by sending a specially crafted request. The request includes a “return URL” parameter, which is stored in a PHP session file. This session file is then sent back to the visitor as part of the HTTP response. The vulnerability was actively exploited in zero-day attacks to breach servers and steal data, as reported by Orange Cyberdefense’s CSIRT.

Input Validation Flaw in Yii Framework

The second vulnerability in the exploit chain is an input validation flaw in the Yii framework, tracked as CVE-2024-58136. This flaw is exploited by sending a malicious JSON payload that causes PHP code execution on the server. This vulnerability is particularly concerning because the Yii framework is widely used by Craft CMS, making many installations potentially vulnerable. The exploitation of this flaw allows attackers to install a PHP-based file manager on the server, further compromising the system.

Exploitation and Impact

Imagine a burglar finding an open window in your house and then discovering a hidden key under the doormat. This is similar to how attackers exploit these vulnerabilities. They start by exploiting the RCE vulnerability (CVE-2025-32432) to store a malicious return URL in the Craft CMS session. Then, they leverage the input validation flaw (CVE-2024-58136) to execute the stored PHP code. This chain of exploits allows attackers to upload additional backdoors and exfiltrate data from the compromised servers, as confirmed by Orange Cyberdefense (BleepingComputer).

Mitigation and Patching

The developers of Craft CMS and the Yii framework have released patches to address these vulnerabilities. The Yii framework flaw (CVE-2024-58136) was fixed in version Yii 2.0.52, released on April 9, 2025. Craft CMS addressed the RCE vulnerability (CVE-2025-32432) in versions 3.9.15, 4.14.15, and 5.6.17, released on April 10, 2025 (BleepingComputer). Despite not updating Yii to the latest version in Craft CMS, the attack chain is considered fixed due to the patch for CVE-2025-32432.

Recommendations for Administrators

Think of your Craft CMS installation as a fortress. To keep it secure, administrators are advised to take several precautionary measures. These include refreshing the security key using the php craft setup/security-key command and updating the CRAFT_SECURITY_KEY environment variable across all production environments. Additionally, administrators should rotate database credentials and consider forcing all users to reset their passwords to mitigate potential data breaches (BleepingComputer).

Additional Vulnerabilities in Craft CMS

In addition to the vulnerabilities discussed above, another RCE vulnerability, identified as CVE-2025-23209, has been reported in Craft CMS versions 4 and 5. This vulnerability requires the installation’s security key to have already been compromised, making exploitation challenging but not impossible. The U.S. Cybersecurity & Infrastructure Security Agency (CISA) has flagged this vulnerability as actively exploited in attacks, urging agencies to patch by March 13, 2025 (BleepingComputer).

Critical Zero-Day Vulnerability

A critical zero-day vulnerability, CVE-2024-56145, was also discovered in Craft CMS, allowing unauthenticated RCE under default configurations. This vulnerability poses a significant threat to the over 150,000 websites powered by Craft CMS globally. The vulnerability was patched within 24 hours of its disclosure, highlighting the importance of timely updates and security measures in content management systems (Sangfor Technologies).

Conclusion

The vulnerabilities in Craft CMS, particularly the RCE exploit chain, underscore the critical need for robust security practices and timely patching. Administrators must remain vigilant and proactive in securing their systems to prevent data breaches and system compromises. The swift response by the Craft CMS team in patching these vulnerabilities is commendable, but ongoing vigilance is necessary to protect against future threats.

Final Thoughts

The Craft CMS RCE exploit chain serves as a stark reminder of the vulnerabilities inherent in widely-used content management systems. The swift response by the developers to patch these vulnerabilities, including CVE-2025-32432 and CVE-2024-58136, is commendable. However, administrators must remain vigilant, ensuring that security keys are refreshed and database credentials rotated. The discovery of additional vulnerabilities, such as CVE-2025-23209, underscores the ongoing threat landscape. Continuous updates and proactive security practices are essential to safeguard against future exploits and protect sensitive data.

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